High heat sealable heavy overwrap material suitable for fast packing

Abstract

The application discloses a high heat-seal performance heavy wrapping film material suitable for rapid packaging, and belongs to the technical field of heavy wrapping film materials, and aims to solve the problems of insufficient heat-seal performance and low mechanical strength of the heavy wrapping film material in the prior art. The heavy wrapping film material is composed of an inner layer, a middle layer and an outer layer with optimized proportions, and each layer is composed of specific polymers and additives to achieve excellent heat-seal performance and mechanical strength. In addition, the application further improves the heat-seal performance and processing performance of the material by introducing specific heat-seal auxiliary agents and antistatic agents. The preparation method comprises precise raw material proportioning, mixing, co-extrusion, cooling and shaping and heat setting treatment. Compared with the prior art, the heavy wrapping film material of the application is suitable for high-speed automatic packaging lines, can significantly improve production efficiency, and at the same time, ensures the reliability and durability of the packaging.

Description

Technical Field

[0001] This invention relates to the field of heavy-duty packaging film technology, and in particular to a high heat-sealing performance heavy-duty packaging film material suitable for rapid packaging. Background Technology

[0002] With the rapid development of modern industry, especially the increasing demand for packaging materials in industries such as food, pharmaceuticals, and chemicals, the market's need for efficient, safe, and environmentally friendly packaging solutions is becoming increasingly urgent. Among many packaging materials, heavy-duty film materials are widely used in the field of rapid packaging due to their excellent protective performance, economy, and ease of automated production.

[0003] Traditional repackaging films typically consist of a multi-layered structure, including an inner, middle, and outer layer, each composed of different polymers to meet specific performance requirements. The inner and outer layers usually need good heat-sealing properties to ensure the packaging is airtight; the middle layer needs high strength and toughness to protect the contents. However, existing repackaging films have limitations, such as insufficient heat-sealing performance, limited mechanical properties, processing complexity, and high cost.

[0004] In terms of heat-sealing performance, traditional heavy-duty film materials may require higher heat-sealing temperatures, which limits packaging speed and increases energy consumption. Furthermore, some materials exhibit poor heat-sealing performance at low temperatures, affecting their application in variable climatic conditions. Regarding mechanical properties, although multi-layer structural designs can improve the overall strength of the material, breakage may still occur under heavy loads or sharp objects. In terms of processing, the complexity of multi-layer co-extrusion processes leads to low production efficiency and increased costs.

[0005] In summary, existing heavy-duty film materials still have room for improvement in terms of heat-sealing performance, mechanical properties, and processing efficiency.

[0006] Chinese invention patent CN112644128B discloses an FFS heavy-duty packaging film and its preparation method, belonging to the field of heavy-duty packaging film technology. The FFS heavy-duty packaging film, from the outside in, consists of an outer layer, a middle layer, and an inner layer, with a thickness ratio of (1-2):(1-2):1. The outer layer comprises 20-40 parts by weight of metallocene linear low-density polyethylene and 60-80 parts by weight of random copolymer polypropylene. The middle layer comprises 40-60 parts by weight of linear low-density polyethylene, 20-40 parts by weight of metallocene linear low-density polyethylene, and 20-40 parts by weight of random copolymer polypropylene. The inner layer comprises 20-40 parts by weight of metallocene linear low-density polyethylene and 60-80 parts by weight of random copolymer polypropylene. This FFS heavy-duty packaging film has high mechanical strength, excellent heat-sealing performance, and a stable coefficient of friction, and can be used in automated packaging lines for large-scale synthetic resin products. However, the FFS heavy-duty packaging film of this invention still suffers from insufficient heat-sealing performance and low mechanical strength. Summary of the Invention

[0007] To address the limitations of existing technologies, this invention aims to provide an improved re-sealing film material with high heat-sealing performance suitable for rapid packaging. By optimizing the raw material ratio and introducing novel auxiliary agents, this invention aims to significantly improve the heat-sealing performance and mechanical strength of the re-sealing film material, while maintaining or improving its production efficiency and packaging quality on high-speed packaging lines.

[0008] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0009] A high heat-sealing performance re-packaging film material suitable for rapid packaging consists of a three-layer structure, namely an inner layer, a middle layer, and an outer layer.

[0010] The inner layer structure is composed of the following components in parts by weight:

[0011] Low-density polyethylene: 10-14 parts

[0012] Linear low-density polyethylene: 45-55 parts

[0013] 10-12 parts of methyl methacrylate-butadiene-styrene copolymer

[0014] Maleic anhydride-grafted polypropylene: 4-6 parts

[0015] Heat sealing aid: 7-9 parts

[0016] Polyethylene wax: 2-4 parts

[0017] Polyurethane: 2-4 parts

[0018] Ethoxylated aliphatic alkylamines: 0.4–0.6 parts.

[0019] The middle layer structure is composed of the following components in parts by weight:

[0020] Metallocene polyethylene: 55-65 parts

[0021] Low-density polyethylene: 5-10 parts

[0022] Ethylene-methyl methacrylate copolymer: 5-10 parts

[0023] Micronized wax: 1-3 parts.

[0024] The outer layer structure is composed of the following components in parts by weight:

[0025] Low-density polyethylene: 10-15 parts

[0026] Linear low-density polyethylene: 45-55 parts

[0027] Ethylene-methacrylic acid copolymer: 10-12 parts

[0028] Maleic anhydride-grafted polypropylene: 4-6 parts

[0029] Heat sealing aid: 7-9 parts

[0030] Polyethylene wax: 2-4 parts

[0031] Polyurethane: 2-4 parts

[0032] Ethoxylated aliphatic alkylamines: 0.4–0.6 parts.

[0033] The inner layer has a thickness of 10–30 μm, the middle layer has a thickness of 5–15 μm, and the outer layer has a thickness of 10–30 μm.

[0034] The heat-sealing aid is prepared as follows, in parts by weight:

[0035] First, 0.1–0.3 parts of fatty alcohol polyoxyethylene ether and 0.5–0.7 parts of polysorbate stearate were dissolved in 60–80 parts of water to prepare a basic aqueous phase. In a pre-designed reactor, 8–12 parts of ethylene, 20–30 parts of vinyl acetate monomer, and 0.2–0.4 parts of azobisisobutyronitrile were used as initiators, followed by the addition of 2–4 parts of triethylsilanol. The polymerization reaction was carried out at 60–80°C and 10–30 MPa under a stirring speed of 400–600 rpm for 30–50 minutes, forming… A homogeneous mixture was prepared. The mixture was then mixed with a base aqueous phase at 50–70°C and 400–600 rpm for 20–40 minutes to form a stable emulsion. The emulsion was then subjected to heat treatment, specifically distillation at 80–120°C for 10–30 minutes to remove unreacted monomers and impurities. Finally, the emulsion was dried using spray drying technology, maintaining a pressure of 30–100 MPa and a hot air temperature of 90–110°C during the drying process, to obtain the desired heat-sealing aid.

[0036] The preparation method of the high heat-sealing performance repackaging film material suitable for rapid packaging is as follows:

[0037] After weighing the required raw materials for each layer according to the proportion, they are mixed separately in a high-speed mixer. The mixing conditions are: temperature 10-50℃, speed 300-1000rpm, time 5-40 minutes. The mixed raw materials are fed into a single-screw extruder for compounding. A three-layer co-extruder is used to fuse the molten materials of each layer and form film bubbles through a blown film die. The film bubbles are cooled and shaped by cooling air at 10-20℃. The cooled film is stretched and heat-shaped using heat-setting rollers. The heat-shaped film is cooled to room temperature by cooling rollers and then wound up.

[0038] The parameters for compounding using the single-screw extruder are: screw temperature 160–200℃, die head temperature 180–210℃, rotation speed 40–100 rpm, and processing pressure 30–50 MPa.

[0039] The three-layer co-extruder fuses the molten material of each layer at a temperature of 180–220°C.

[0040] The temperature at which the heat-setting roller heats the film is 60–90°C.

[0041] In this invention, the functions of each substance are as follows:

[0042] Low-density polyethylene (LDPE) provides films with flexibility and impact resistance.

[0043] Linear low-density polyethylene (LLDPE) reinforces the strength and puncture resistance of films.

[0044] Methyl methacrylate-butadiene-styrene copolymer increases the impact resistance and flexibility of the film.

[0045] Maleic anhydride-grafted polypropylene improves the heat-sealing and mechanical properties of the film.

[0046] Heat-sealing aids improve the heat-sealing properties of films, making them easier to heat-seal at lower temperatures.

[0047] Polyethylene wax, as a processing aid, improves the processing performance of films and increases their slip properties.

[0048] Abrasion resistance and tear resistance of polyurethane reinforced films.

[0049] Ethoxylated aliphatic alkylamines act as antistatic agents, reducing static electricity buildup in films during processing and use.

[0050] Metallocene polyethylene improves the transparency and strength of films.

[0051] Ethylene-methyl methacrylate copolymers offer good thermal stability and adhesive properties.

[0052] Micronized wax improves the smoothness and anti-blocking properties of the film.

[0053] In the preparation of heat-sealing aids, N-aminoethyl-3-aminopropyltriethoxysilane and propyltriethoxysilane participate in the polymerization reaction as active monomers.

[0054] In the preparation of heat-sealing aids, fatty alcohol polyoxyethylene ethers form a basic aqueous phase together with polysorbate stearate.

[0055] Azobisisobutyronitrile (AIBN) is used as an initiator to initiate the polymerization reaction of the monomers.

[0056] The combination and interaction of these substances give the final repackaging film material excellent heat-sealing, mechanical, and processing properties, making it suitable for rapid packaging requirements.

[0057] Compared with existing technologies, it has the following advantages:

[0058] 1) By using specific heat-sealing aids, this invention can improve the heat-sealing performance and mechanical properties of heavy-duty packaging film materials, enabling its use on high-speed packaging lines and improving production efficiency.

[0059] 2) The heavy-duty film material of the present invention enhances the overall mechanical properties of the material, including tensile strength and elongation at break, through the inner, middle and outer layer structure design and the various polymers and additives used.

[0060] 3) The use of additives such as polyethylene wax and micronized wax in this invention improves the processing performance of the material, including the flowability and extensibility during extrusion and heat sealing. The addition of antistatic agents such as ethoxylated aliphatic alkylamines reduces the accumulation of static electricity in the material during processing and use, thereby improving safety. Detailed Implementation

[0061] Main source of materials:

[0062] Low-density polyethylene: Shanghai Juyizhi Plastics Co., Ltd., grade: N210.

[0063] Linear low-density polyethylene: Shenzhen Minjian Plastics Co., Ltd., Item No.: LL 8460.

[0064] Methyl methacrylate-butadiene-styrene copolymer: Ningbo Jiuli New Materials Co., Ltd., grade: EM500.

[0065] Maleic anhydride-grafted polypropylene: Dongguan Kangjin New Material Technology Co., Ltd., Product Model: 820.

[0066] Polyethylene wax: Dongguan Kangjin New Material Technology Co., Ltd., Product model: LA-102, CAS: 9002-88-4.

[0067] Polyurethane: Shenzhen Ruidasheng Plastics Co., Ltd., Product No.: TPU powder.

[0068] Ethoxylated aliphatic alkylamines: Haian Petrochemical Plant, Jiangsu Province, pH: 5-7, amine value mgKOH / g: 195-220.

[0069] Metallocene polyethylene: Ningbo Jinchi Plastics Co., Ltd., grade: SM.

[0070] Ethylene-methyl methacrylate copolymer: Suzhou Lutuo Materials Co., Ltd., brand name: SWA210.

[0071] Micronized wax: Suzhou Huiwangcheng Chemical Co., Ltd., Product No.: 0605.

[0072] Ethylene-methacrylic acid copolymer: Guangzhou Jinkai Chemical Co., Ltd., item number: 599.

[0073] Ethoxylated aliphatic alkylamine fatty alcohol polyoxyethylene ether: Shandong Changyuan Chemical Co., Ltd., Model: AEO-9.

[0074] Polysorbate stearate: Jiangsu Haian Petrochemical Plant, model: t-60.

[0075] In this invention, the weighing and mixing of raw materials ensures that various raw materials are mixed in precise proportions, providing uniform materials for subsequent processing steps. Using a high-speed mixer can achieve uniform mixing in a shorter time, while simultaneously controlling mixing conditions to guarantee the physical and chemical stability of the raw materials.

[0076] The mixed raw materials are melted and kneaded to ensure that all components are fully integrated. Screw temperature, die temperature, rotation speed, and processing pressure are controlled to achieve optimal melting and flowability, preparing the material for co-extrusion.

[0077] The molten materials of the inner, middle, and outer layers are fused together in the same extrusion process to form a three-layer film. By controlling the fusion temperature and die design, it is ensured that the materials of each layer can be uniformly combined during the extrusion process to form a stable three-layer structure.

[0078] The membrane bubble is cooled by cooling air to rapidly set its shape and maintain the required thickness and physical properties. The temperature and flow rate of the cooling air need to be matched with the cooling requirements of the membrane to ensure that the membrane does not deform during the cooling process.

[0079] Stretching the cooled film improves its mechanical strength and heat-sealing properties. The stretching process can induce the orientation of polymer molecular chains, thereby enhancing the physical properties of the film.

[0080] Heat-setting rollers are used to heat-treat films to stabilize their dimensions and properties. The temperature of the heat-setting rollers needs to be precisely controlled to ensure that the film achieves the desired physical properties after heat setting.

[0081] The heat-set film is cooled and then wound into rolls for subsequent processing and use. The temperature and speed of the cooling rollers need to be matched with the cooling rate of the film to prevent heat buildup during winding.

[0082] Heat-sealing aids that can improve the heat-sealing performance of films were prepared. These aids, containing specific functional groups, were synthesized via polymerization. These functional groups can interact with the polymer matrix, improving the adhesion and thermal stability of the heat-sealing layer.

[0083] The overall design concept involves precisely controlling each step, including raw material proportioning, mixing, melting, extrusion, cooling, stretching, shaping, and winding, to prepare a heavy-duty film material with excellent heat-sealing and mechanical properties. Simultaneously, the heat-sealing performance of the film is further improved through the preparation of heat-sealing aids to meet the demands of rapid packaging.

[0084] Example 1

[0085] The high heat-sealing performance repackaging film material suitable for rapid packaging consists of a three-layer structure, namely an inner layer, a middle layer, and an outer layer.

[0086] The inner layer structure is composed of the following components in parts by weight:

[0087] Low-density polyethylene: 12 parts

[0088] Linear low-density polyethylene: 50 parts

[0089] methyl methacrylate-butadiene-styrene copolymer: 11 parts

[0090] Maleic anhydride-grafted polypropylene: 5 parts

[0091] Heat sealing aid: 8 parts

[0092] Polyethylene wax: 3 parts

[0093] Polyurethane: 3 parts

[0094] Ethoxylated aliphatic alkylamines: 0.5 parts.

[0095] The middle layer structure is composed of the following components in parts by weight:

[0096] Metallocene polyethylene: 60 parts

[0097] Low-density polyethylene: 8 parts

[0098] Ethylene-methyl methacrylate copolymer: 7 parts

[0099] Micronized wax: 2 parts.

[0100] The outer layer structure is composed of the following components in parts by weight:

[0101] Low-density polyethylene: 12 parts

[0102] Linear low-density polyethylene: 50 parts

[0103] Ethylene-methacrylic acid copolymer: 11 parts

[0104] Maleic anhydride-grafted polypropylene: 5 parts

[0105] Heat sealing aid: 8 parts

[0106] Polyethylene wax: 3 parts

[0107] Polyurethane: 3 parts

[0108] Ethoxylated aliphatic alkylamines: 0.5 parts.

[0109] The preparation method of the high heat-sealing performance repackaging film material suitable for rapid packaging is as follows:

[0110] After weighing the required raw materials for each layer according to the proportions, they are mixed separately in a high-speed mixer under the following conditions: temperature 30℃, speed 500 rpm, time 30 minutes. The mixed raw materials are then fed into a single-screw extruder for compounding, with a screw temperature of 180℃, a die head temperature of 200℃, a speed of 80 rpm, and a processing pressure of 40 MPa. A three-layer co-extruder is used to fuse the molten materials of each layer at a fusion temperature of 200℃. The molten materials are then formed into film bubbles through a blown film die. The film bubbles are cooled and shaped by a 15℃ cooling air. The cooled film is then stretched and heat-shaped using a heat-setting roller at a temperature of 80℃. The heat-shaped film is then cooled to room temperature by a cooling roller and then wound up. The thickness of the inner layer is 20 μm, the middle layer is 10 μm, and the outer layer is 20 μm.

[0111] The heat-sealing aid is prepared as follows:

[0112] First, 0.2 g of fatty alcohol polyoxyethylene ether and 0.6 g of polysorbate stearate were dissolved in 70 g of water to prepare a basic aqueous phase. In a pre-designed reactor, 10 g of ethylene, 25 g of vinyl acetate monomer, and 0.3 g of azobisisobutyronitrile were used as initiators, and 3 g of triethylsilanol was added. The polymerization reaction was carried out at 70 °C and 20 MPa pressure, with stirring at 500 rpm for 40 minutes to form a homogeneous mixture. The mixture was then mixed with the basic aqueous phase at 60 °C and 500 rpm stirring for 30 minutes to form a stable emulsion. The emulsion was then heat-treated by distillation at 100 °C for 20 minutes to remove unreacted monomers and impurities. Finally, the emulsion was dried using spray drying technology, maintaining a pressure of 80 MPa and a hot air temperature of 100 °C during the drying process, to obtain the desired heat-sealing aid.

[0113] Example 2

[0114] The preparation method of a high heat-sealing performance repackaging film material suitable for rapid packaging is basically the same as that in Example 1, except that the preparation method of the heat-sealing auxiliary agent is different.

[0115] The heat-sealing aid is prepared as follows:

[0116] First, 0.2 g of fatty alcohol polyoxyethylene ether and 0.6 g of polysorbate stearate were dissolved in 70 g of water to prepare a basic aqueous phase. In a pre-designed reactor, 10 g of ethylene, 25 g of vinyl acetate monomer, and 0.3 g of azobisisobutyronitrile were used as initiators, and 3 g of dimethyl silanediol was added. The polymerization reaction was carried out at 70 °C and 20 MPa pressure, with stirring at 500 rpm for 40 minutes to form a homogeneous mixture. The mixture was then mixed with the basic aqueous phase at 60 °C and 500 rpm stirring for 30 minutes to form a stable emulsion. The emulsion was then heat-treated by distillation at 100 °C for 20 minutes to remove unreacted monomers and impurities. Finally, the emulsion was dried using spray drying technology, maintaining a pressure of 80 MPa and a hot air temperature of 100 °C during the drying process, to obtain the desired heat-sealing aid.

[0117] Example 3

[0118] The preparation method of a high heat-sealing performance repackaging film material suitable for rapid packaging is basically the same as that in Example 1, except that the preparation method of the heat-sealing auxiliary agent is different.

[0119] The heat-sealing aid is prepared as follows:

[0120] First, 0.2 g of fatty alcohol polyoxyethylene ether and 0.6 g of polysorbate stearate were dissolved in 70 g of water to prepare a basic aqueous phase. In a pre-designed reactor, 10 g of ethylene, 25 g of vinyl acetate monomer, and 0.3 g of azobisisobutyronitrile were used as initiators, and 3 g of N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane was added. The polymerization reaction was carried out at 70 °C and 20 MPa pressure, and this process was continued for 40 minutes with a stirring speed of 500 rpm to form a homogeneous mixture. The mixture obtained above was mixed with the basic aqueous phase at 60 °C and 500 rpm stirring speed, and stirred continuously for 30 minutes to form a stable emulsion. The prepared emulsion was heat-treated, specifically by distillation at 100 °C for 20 minutes to remove unreacted monomers and impurities. Finally, the emulsion was dried using spray drying technology, maintaining a pressure of 80 MPa and a hot air temperature of 100 °C during the drying process, to obtain the desired heat-sealing aid.

[0121] Example 4

[0122] The preparation method of a high heat-sealing performance repackaging film material suitable for rapid packaging is basically the same as that in Example 1, except that the preparation method of the heat-sealing auxiliary agent is different.

[0123] The heat-sealing aid is prepared as follows:

[0124] First, 0.2 g of fatty alcohol polyoxyethylene ether and 0.6 g of polysorbate stearate were dissolved in 70 g of water to prepare a basic aqueous phase. In a pre-designed reactor, 10 g of ethylene, 25 g of vinyl acetate monomer, and 0.3 g of azobisisobutyronitrile were used as initiators, and 3 g of 3-(diethoxymethylsilyl)propylamine was added. The polymerization reaction was carried out at 70 °C and 20 MPa pressure, and this process was continued for 40 minutes at a stirring speed of 500 rpm to form a homogeneous mixture. The mixture obtained above was mixed with the basic aqueous phase at 60 °C and a stirring speed of 500 rpm, and stirred continuously for 30 minutes to form a stable emulsion. The prepared emulsion was heat-treated, specifically by distillation at 100 °C for 20 minutes to remove unreacted monomers and impurities. Finally, the emulsion was dried using spray drying technology, maintaining a pressure of 80 MPa and a hot air temperature of 100 °C during the drying process, to obtain the desired heat-sealing aid.

[0125] Example 5

[0126] The preparation method of a high heat-sealing performance repackaging film material suitable for rapid packaging is basically the same as that in Example 1, except that the preparation method of the heat-sealing auxiliary agent is different.

[0127] The heat-sealing aid is prepared as follows:

[0128] First, 0.2 g of fatty alcohol polyoxyethylene ether and 0.6 g of polysorbate stearate were dissolved in 70 g of water to prepare a basic aqueous phase. In a pre-designed reactor, 10 g of ethylene, 25 g of vinyl acetate monomer, and 0.3 g of azobisisobutyronitrile were used as initiators, and 3 g of N-aminoethyl-3-aminopropyltriethoxysilane was added. The polymerization reaction was carried out at 70 °C and 20 MPa pressure, and this process was continued for 40 minutes at a stirring speed of 500 rpm to form a homogeneous mixture. The mixture obtained above was mixed with the basic aqueous phase at 60 °C and 500 rpm stirring speed, and stirred continuously for 30 minutes to form a stable emulsion. The prepared emulsion was heat-treated, specifically by distillation at 100 °C for 20 minutes to remove unreacted monomers and impurities. Finally, the emulsion was dried using spray drying technology, maintaining a pressure of 80 MPa and a hot air temperature of 100 °C during the drying process, to obtain the desired heat-sealing aid.

[0129] Example 6

[0130] The preparation method of a high heat-sealing performance repackaging film material suitable for rapid packaging is basically the same as that in Example 1, except that the preparation method of the heat-sealing auxiliary agent is different.

[0131] The heat-sealing aid is prepared as follows:

[0132] First, 0.2 g of fatty alcohol polyoxyethylene ether and 0.6 g of polysorbate stearate were dissolved in 70 g of water to prepare a basic aqueous phase. In a pre-designed reactor, 10 g of ethylene, 25 g of vinyl acetate monomer, and 0.3 g of azobisisobutyronitrile were used as initiators, and 3 g of ureapropyltriethoxysilane was added. The polymerization reaction was carried out at 70 °C and 20 MPa pressure, with stirring at 500 rpm for 40 minutes to form a homogeneous mixture. The mixture was then mixed with the basic aqueous phase at 60 °C and 500 rpm stirring for 30 minutes to form a stable emulsion. The emulsion was then heat-treated by distillation at 100 °C for 20 minutes to remove unreacted monomers and impurities. Finally, the emulsion was dried using spray drying technology, maintaining a pressure of 80 MPa and a hot air temperature of 100 °C during the drying process, to obtain the desired heat-sealing aid.

[0133] Example 7

[0134] The preparation method of a high heat-sealing performance repackaging film material suitable for rapid packaging is basically the same as that in Example 1, except that the preparation method of the heat-sealing auxiliary agent is different.

[0135] The heat-sealing aid is prepared as follows:

[0136] First, 0.2 g of fatty alcohol polyoxyethylene ether and 0.6 g of polysorbate stearate were dissolved in 70 g of water to prepare a basic aqueous phase. In a pre-designed reactor, 10 g of ethylene, 25 g of vinyl acetate monomer, and 0.3 g of azobisisobutyronitrile were used as initiators, and 3 g of propyltriethoxysilane isocyanate was added. The polymerization reaction was carried out at 70 °C and 20 MPa pressure, and this process was continued for 40 minutes with a stirring speed of 500 rpm to form a homogeneous mixture. The mixture obtained above was mixed with the basic aqueous phase at 60 °C and 500 rpm stirring speed, and stirred continuously for 30 minutes to form a stable emulsion. The prepared emulsion was heat-treated, specifically by distillation at 100 °C for 20 minutes to remove unreacted monomers and impurities. Finally, the emulsion was dried using spray drying technology, maintaining a pressure of 80 MPa and a hot air temperature of 100 °C during the drying process, to obtain the desired heat-sealing aid.

[0137] Example 8

[0138] The preparation method of a high heat-sealing performance repackaging film material suitable for rapid packaging is basically the same as that in Example 1, except that the preparation method of the heat-sealing auxiliary agent is different.

[0139] The heat-sealing aid is prepared as follows:

[0140] First, 0.2 g of fatty alcohol polyoxyethylene ether and 0.6 g of polysorbate stearate were dissolved in 70 g of water to prepare a basic aqueous phase. In a pre-designed reactor, 10 g of ethylene, 25 g of vinyl acetate monomer, and 0.3 g of azobisisobutyronitrile were used as initiators, and 3 g of methyl-(3-propyl isocyanate)dimethylsilane was added. The polymerization reaction was carried out at 70 °C and 20 MPa pressure, and this process was continued at a stirring speed of 500 rpm for 40 minutes to form a homogeneous mixture. The mixture obtained above was mixed with the basic aqueous phase at 60 °C and 500 rpm stirring speed, and stirred continuously for 30 minutes to form a stable emulsion. The prepared emulsion was heat-treated, specifically by distillation at 100 °C for 20 minutes to remove unreacted monomers and impurities. Finally, the emulsion was dried using spray drying technology, maintaining a pressure of 80 MPa and a hot air temperature of 100 °C during the drying process, to obtain the desired heat-sealing aid.

[0141] Example 9

[0142] The preparation method of a high heat-sealing performance repackaging film material suitable for rapid packaging is basically the same as that in Example 1, except that the preparation method of the heat-sealing auxiliary agent is different.

[0143] The heat-sealing aid is prepared as follows:

[0144] First, 0.2 g of fatty alcohol polyoxyethylene ether and 0.6 g of polysorbate stearate were dissolved in 70 g of water to prepare a basic aqueous phase. In a pre-designed reactor, 10 g of ethylene, 25 g of vinyl acetate monomer, and 0.3 g of azobisisobutyronitrile were used as initiators, and 3 g of 3-isocyanopropyl dimethylchlorosilane was added. The polymerization reaction was carried out at 70 °C and 20 MPa pressure, and this process was continued for 40 minutes with a stirring speed of 500 rpm to form a homogeneous mixture. The mixture obtained above was mixed with the basic aqueous phase at 60 °C and 500 rpm stirring speed, and stirred continuously for 30 minutes to form a stable emulsion. The prepared emulsion was heat-treated, specifically by distillation at 100 °C for 20 minutes to remove unreacted monomers and impurities. Finally, the emulsion was dried using spray drying technology, maintaining a pressure of 80 MPa and a hot air temperature of 100 °C during the drying process, to obtain the desired heat-sealing aid.

[0145] Example 10

[0146] The preparation method of a high heat-sealing performance repackaging film material suitable for rapid packaging is basically the same as that in Example 1, except that the preparation method of the heat-sealing auxiliary agent is different.

[0147] The heat-sealing aid is prepared as follows:

[0148] First, 0.2 g of fatty alcohol polyoxyethylene ether and 0.6 g of polysorbate stearate were dissolved in 70 g of water to prepare a basic aqueous phase. In a pre-designed reactor, 10 g of ethylene, 25 g of vinyl acetate monomer, and 0.3 g of azobisisobutyronitrile (AIBN) were used as initiators. Then, 1.5 g of N-aminoethyl-3-aminopropyltriethoxysilane and 1.5 g of propyltriethoxysilane isocyanate were added. The polymerization reaction was carried out at 70 °C and 20 MPa under a stirring speed of 500 rpm. The mixture was stirred for 40 minutes to form a homogeneous mixture. The mixture was then mixed with a base aqueous phase at 60°C and 500 rpm for 30 minutes to form a stable emulsion. The emulsion was then subjected to heat treatment, specifically distillation at 100°C for 20 minutes to remove unreacted monomers and impurities. Finally, the emulsion was dried using spray drying technology, maintaining a pressure of 80 MPa and a hot air temperature of 100°C during the drying process, to obtain the desired heat-sealing aid.

[0149] Comparative Example 1

[0150] The preparation method of a high heat-sealing performance repackaging film material suitable for rapid packaging is basically the same as that in Example 1, except that the preparation method of the heat-sealing auxiliary agent is different.

[0151] The heat-sealing aid is prepared as follows:

[0152] First, 0.2 g of fatty alcohol polyoxyethylene ether and 0.6 g of polysorbate stearate were dissolved in 70 g of water to prepare a basic aqueous phase. In a pre-designed reactor, 10 g of ethylene, 25 g of vinyl acetate monomer, and 0.3 g of azobisisobutyronitrile (AIBN) were used as initiators, and polymerization was carried out at 70 °C and 20 MPa pressure. This process was continued for 40 minutes with a stirring speed of 500 rpm to form a homogeneous mixture. The resulting mixture was then mixed with the basic aqueous phase at 60 °C and 500 rpm with stirring for 30 minutes to form a stable emulsion. The prepared emulsion was then heat-treated by distillation at 100 °C for 20 minutes to remove unreacted monomers and impurities. Finally, the emulsion was dried using spray drying technology, maintaining a pressure of 80 MPa and a hot air temperature of 100 °C during the drying process, ultimately yielding the desired heat-sealing aid.

[0153] Comparative Example 2

[0154] The high heat-sealing performance repackaging film material suitable for rapid packaging consists of a three-layer structure, namely an inner layer, a middle layer, and an outer layer.

[0155] The inner layer structure is composed of the following components by weight:

[0156] Low-density polyethylene: 12 parts

[0157] Linear low-density polyethylene: 50 parts

[0158] methyl methacrylate-butadiene-styrene copolymer: 11 parts

[0159] Maleic anhydride-grafted polypropylene: 5 parts

[0160] Polyethylene wax: 3 parts

[0161] Polyurethane: 3 parts

[0162] Ethoxylated aliphatic alkylamines: 0.5 parts.

[0163] The middle layer structure is composed of the following components by weight:

[0164] Metallocene polyethylene: 60 parts

[0165] Low-density polyethylene: 8 parts

[0166] Ethylene-methyl methacrylate copolymer: 7 parts

[0167] Micronized wax: 2 parts.

[0168] The outer layer structure is composed of the following components by weight:

[0169] Low-density polyethylene: 12 parts

[0170] Linear low-density polyethylene: 50 parts

[0171] Ethylene-methacrylic acid copolymer: 11 parts

[0172] Maleic anhydride-grafted polypropylene: 5 parts

[0173] Polyethylene wax: 3 parts

[0174] Polyurethane: 3 parts

[0175] Ethoxylated aliphatic alkylamines: 0.5 parts.

[0176] The preparation method of the high heat-sealing performance repackaging film material suitable for rapid packaging is the same as that in Example 1.

[0177] Test Example 1

[0178] Heat sealing performance test

[0179] The high heat-sealing performance repackaging film materials prepared in the embodiments and comparative examples of this invention were tested according to QB / T 2358-1998 "Test Method for Heat Seal Strength of Plastic Film Packaging Bags". The heat sealing temperature was 120℃, and the test results are shown in Table 1.

[0180] Table 1

[0181]

[0182]

[0183] Test Example 2

[0184] Mechanical property testing

[0185] The high heat-sealing performance re-coating film materials prepared in the embodiments and comparative examples of the present invention were tested according to GB / T 1040.3-2006 "Determination of tensile properties of plastics - Part 3 Test conditions for films and strips". The test results are shown in Table 2.

[0186] Table 2

[0187] Experimental protocol Tensile strength (N / 15mm) Elongation at break (%) Example 1 48.4 761 Example 2 49.0 762 Example 3 52.6 790 Example 4 52.0 796 Example 5 53.4 813 Example 6 53.1 796 Example 7 53.9 818 Example 8 50.6 767 Example 9 51.6 786 Example 10 56.3 839 Comparative Example 1 43.7 716 Comparative Example 2 38.6 672

[0188] As can be seen from test examples 1 and 2, the high heat-sealing performance re-coating film material obtained in Example 10 of the present invention has good heat-sealing performance and mechanical properties.

[0189] The heat-sealing aid in Example 10 performed optimally likely because it employed a blend of N-aminoethyl-3-aminopropyltriethoxysilane and propyltriethoxysilane isocyanate. N-aminoethyl-3-aminopropyltriethoxysilane contains amino and triethoxysilane groups, which can react with reactants or form hydrogen bonds, enhancing the adhesive properties of the heat-sealing layer. propyltriethoxysilane contains isocyanate groups, highly reactive groups that can react with active hydrogen atoms (such as hydroxyl or amino groups) to form stable urethane bonds. The isocyanate group is a key functional group in the heat-sealing aid because it reacts rapidly with hydroxyl or amino groups to form strong chemical bonds, thereby improving the adhesive strength and thermal stability of the heat-sealing layer. The blended silanes, due to their different functional groups, may have better compatibility with the polymer, contributing to the formation of a uniform heat-sealing layer. Two different silanes may produce a synergistic effect, with one silane improving the flexibility and adhesion of the heat-sealing layer, while the other enhances its mechanical strength and thermal stability. The silane used in Example 10 has a longer carbon chain and more functional groups, which may contribute to the formation of a more complex network structure in the polymer matrix, thereby improving the overall performance of the heat-sealing layer. The use of the compounded silanes in Example 10 may have improved the mechanical properties of the heat-sealing layer, such as tensile strength and elongation at break, as demonstrated in mechanical property tests.

[0190] In summary, the combination of the two silanes in Example 10 likely works through multiple mechanisms, including enhanced intermolecular forces, improved polarity matching, increased reactivity, formation of cross-linked structures, and synergistic effects, resulting in the superior heat-sealing performance of the re-coating film material in Example 10 in both heat-sealing and mechanical property tests. In contrast, other examples may have used silanes with single functional groups, failing to generate sufficient synergistic effects or compatibility, leading to inferior performance compared to Example 10.

Claims

1. A high heat-sealing performance re-packaging film material suitable for rapid packaging, characterized in that, It consists of three layers: an inner layer, a middle layer, and an outer layer. The inner layer is composed of the following components by weight: Low-density polyethylene: 10-14 parts Linear low-density polyethylene: 45-55 parts 10-12 parts of methyl methacrylate-butadiene-styrene copolymer Maleic anhydride-grafted polypropylene: 4-6 parts Heat sealing aid: 7-9 parts Polyethylene wax: 2-4 parts Polyurethane: 2-4 parts Ethoxylated aliphatic alkylamines: 0.4~0.6 parts; The heat-sealing aid is prepared as follows, in parts by weight: First, 0.1–0.3 parts of fatty alcohol polyoxyethylene ether and 0.5–0.7 parts of polysorbate stearate are dissolved in 60–80 parts of water to prepare a basic aqueous phase. In a pre-designed reactor, 8–12 parts of ethylene, 20–30 parts of vinyl acetate monomer, and 0.2–0.4 parts of azobisisobutyronitrile are used as initiators. Then, 1.5 parts of N-aminoethyl-3-aminopropyltriethoxysilane and 1.5 parts of propyltriethoxysilane are added. The polymerization reaction is carried out at 60–80°C and 10–30 MPa, with a stirring speed of 400–600 rpm. The mixture is stirred at 50-70°C for 30-50 minutes to form a homogeneous mixture. This mixture is then mixed with a base aqueous phase at 400-600 rpm for 20-40 minutes to form a stable emulsion. The emulsion is then heat-treated by distillation at 80-120°C for 10-30 minutes to remove unreacted monomers and impurities. Finally, the emulsion is dried using spray drying technology, maintaining a pressure of 30-100 MPa and a hot air temperature of 90-110°C during the drying process, ultimately yielding the desired heat-sealing aid.

2. The high heat-sealing performance repackaging film material suitable for rapid packaging as described in claim 1, characterized in that, The middle layer structure is composed of the following components in parts by weight: Metallocene polyethylene: 55-65 parts Low-density polyethylene: 5-10 parts Ethylene-methyl methacrylate copolymer: 5-10 parts Micronized wax: 1-3 parts.

3. The high heat-sealing performance repackaging film material suitable for rapid packaging as described in claim 1, characterized in that, The outer layer structure is composed of the following components in parts by weight: Low-density polyethylene: 10-15 parts Linear low-density polyethylene: 45-55 parts Ethylene-methacrylic acid copolymer: 10-12 parts Maleic anhydride-grafted polypropylene: 4-6 parts Heat sealing aid: 7-9 parts Polyethylene wax: 2-4 parts Polyurethane: 2-4 parts Ethoxylated aliphatic alkylamines: 0.4~0.6 parts.

4. The high heat-sealing performance repackaging film material suitable for rapid packaging as described in claim 1, characterized in that, The inner layer has a thickness of 10~30μm, the middle layer has a thickness of 5~15μm, and the outer layer has a thickness of 10~30μm.

5. A method for preparing a high heat-sealing performance repackaging film material suitable for rapid packaging as described in any one of claims 1 to 4, characterized in that, The method is as follows: After weighing the required raw materials for each layer according to the proportion, they are mixed separately in a high-speed mixer. The mixing conditions are: temperature 10~50℃, speed 300~1000rpm, time 5~40 minutes. The mixed raw materials are fed into a single screw extruder for compounding. A three-layer co-extruder is used to fuse the molten materials of each layer and form film bubbles through a blown film die. The film bubbles are cooled and shaped by cooling air at 10~20℃. The cooled film is stretched and heat-shaped using a heat-setting roller. The heat-shaped film is cooled to room temperature by a cooling roller and then wound up.

6. The method as described in claim 5, characterized in that, The parameters for compounding using the single-screw extruder are: screw temperature 160~200℃, die head temperature 180~210℃, rotation speed 40~100 rpm, and processing pressure 30~50MPa.

7. The method as described in claim 5, characterized in that, The three-layer co-extruder fuses the molten material of each layer at a temperature of 180~220℃.

8. The method as described in claim 5, characterized in that, The temperature at which the heat-setting roller heats the film is 60~90℃.

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